I've been working with 5x7 for a little while and I find it to be not much more of a pain than MF or 35mm. The difference is that you end up taking a lot less pictures, but it takes about the same amount of time to develop them. For instance, if I'm doing portraits with someone, I'm going to shoot 1-2 rolls of 120 film. If I'm shooting 5x7, I'll shoot 2-4 frames. It makes you really focus. But in the end, I'm only interested in having one really good picture of a situation. If things are going well, and there's more than one good picture on a roll of 120, I'm still going to have to pick only 1.
If you are coming from digital, and you really want to twist your head around, try a 4x5. In fact, try the one I have listed for sale